Slow response on right clicks

The problem at hand is this: My PC at my lab, running Windows XP, was taking incruciatingly long time, at times around 30 seconds, to pop up the menu when right clicked on any "application" file, like doc, jpg, mp3 etc. However, it was working fine on exe files. Moreover, when double clicked on an application file, it was taking approximately the same long delay to launch the application.

I started the trouble shooting by first looking through the task manager to see what process moves up in CPU time / memory usage when I right click an application file. That provided me with no great information as "explorer.exe" got up the list, however not taking much resources. I did an antivirus check, a spyware check etc., as well, but did not help. Then, I tried disabling the firewall, uninstalling Norton Antivirus, stopping IIS etc, as mentioned in some other forums.

It was when I was about to give up and was thinking about backing the data and reformatting the computer that I learnt about a tool by name "FileMon.Exe" which monitors the files accessed by other files - didn't help! However, from the same site that provides FileMon, http://www.sysinternals.com/, I found a new utility called RegMon.Exe that monitors the activity on the registry and the various registry keys accessed by other programs. This one proved to be my saviour when I found that explorer.exe was the one taking too much time when I right click or launch an application file. However, explorer.exe was spending this time to probe the photoshop executable, may be to check file associations. This prompted me to uninstall Photoshop, but even after this, RegMon.exe continues to show that a registry key with the Photoshop executable as value was being probed and most of the time was spent there. Now, I did a search in registry using RegEdit and removed all values/keys that contains "Photoshop". I closed regedit, and, voila! the menus now pop-up with a bang!!

So... next time,some similar problem arises... RegMon is my man!